Automatic poppet-valve control



-C. SQ BURNE TT AUTOMATIC PCPPET VALVE CONTROL Ma c'h 31, 1931.

Filed NW. 26. '1928 2 Shee ts-Sheet 1 A'r'romlev.

'fl 1931:- Y c. s. BURNETT 1,798,185

AUTOMATIC POPPET VALVECONTROL Fi led Nov. 26, 1928 zsneet -sheez 2Patented Mar. 31, 1931 CHARLES e BHBNET NE 5A1?E341QISQQQ-CALHQRNIAAUTOMATIC POPPET-VALVE CONTROL Application filed Novemb'er 26, 1928.Serial No; 32L999.

(GRANTEDUNDER THE'ACT 0E MARGHL3Q1883, ASLAMENFDEDUAPRIQ30;1928'; 370'0'; G. 757) a This invention described herein may be manufactured andusedby or for the Government for governmental purposes, Withoutvthree-payment to me of-any royaltythereon;

ycinvention relatesto a means for con: trolling the valves of eng nesandmore particularly to a Variable valve-actuating cama-nd ggvernor controltherefor, the former so:v constructed, that the dwell, or, inotherWords;; the cir'cumferentialZ extent of: the

dwell, thereof, may be varied bythe latter.

The cam issubject to beingused in anycdevice wherein; cams are employedbut is particularly adaptable to use, With engines to actuate the intakeand, exhaust valves thereof, a multiplicity of such cams capableof;being 'aositioned at-any desired angle oftheir plane of rotation onthe same cam shaft, so as ,to be rotated thereby a-ndcontrolled byv thesame varying agency.

Not;only isthe dwell susceptible of being altered manually but-it maybechanged during the rotation of the cam byrmea-ns ofa, governorcontrolled mechanism or the like,

andthe otherdesigned to be moved relative to "first part as to f {IValuation in hen e-1n: :dwell'.

ble oiflbeing rotated by the governing means as thespeed' *a-ries. Thegoverning means, producesa a'elatiye-iotati n to fgthe, rod-with respectto; the camshaft asjlthe speedflof the device operating; the meansfluctuateswith the result that ;the pin is: moved-to roj-i tate the.movablepartabout theicam shaft asa center to vary the dwell so as toeffect;- a-

greater or lesser clurationiofthe exhanst or ntake-reli th ase mar-be;

nwbi c of my: v ntio is toproridea am-whose, well be varied; automate@81 3: by he pera -i 10 th dW 'Q' IkWhiGh-1 tr mbqdi'd; m v tljerxebieqt;f:n1y-:inyehtion eielto proi-a vide. a valveactuating cam to varyautomati cally the-timeoi opening and-closing of a, valve accordance,With the speed ofthe driving mechanism Without. regard to the loadcarried b the driving mechanism; a

A- further o 'jectcis to effectthelast mentioned-objects, Withoutincreasing. or, decreasingthe lift ofthe valve, V

Anotherobject or the invention. is to provide a cam' .Which variestheduration ofthe exhaustor, inlet period of .thevalves' of an iii-- ternalcombustion engine asajfunction of the engine speed. l' a Animportantbbjectis to make it-possible andipracticablenfirst athighspeeds', to clelay the time ofclosing, the intake valve of internalcombustion engines using gas fuel for; the purpose of, taking advantageof @the inertia of the inrushing gas so as: to. permit. thegas to enteragafinstthe 'initial r,etarding pressuredileto the return movement ofthe piston on its compression strolgeg second, at

ready enteredinto the combustion chamber h from beingforced outlby thepistononwits:

compression strokerthird; at highspeeds to adv nce he opening, time othe exhaust valve to allow time for fulltexhaustgaftert combustion andexpansiongdand fourth, at low speeclsto, delay the 'unnecessarilyearlyop ni gnf the e hau'SilVillYe.

The movable part is engaged by a-apin carried .on; a rotatable, butaxially fixed rod that is ourna-lledawith-in the cam; shaft anrl -capa-In order my invention may bereadily Q Bl' L Qd, Ifife'rence is had tothe accomr panying drawings iormingapart of this igur 3r pres ntsaperspe tive of-Vthat part of the cam 7 Which' is fixed with respect tothe camshaft.

"Figure i is-a perspective of,the. movable campartr Y i 3 v Suitablyjeurnalled-in an engineso as to be rotated'thereby is a hollpw camshaft{1 carrying a governor mechanisni, broadly designated: asE-A,positioned'thereonsofas to; be capable ozf :hein'g-trotated withith' camsha it; BlIe-.i:l1o 1'lnw.=sha ft .i'szaprovided with a step bearing 2and a second bearing 3 providedto support a rod 4 rotatably but axiallyfixed. The rod is spirally threaded at its outer end and is providedwith an oil passage 6 within it for purposes which will hereinafterappear. A disc 5 provided with a multiplicity of pins 7 is fixed to theend of the cam shaft in any desired manner so as to rotate therewith,the pins designed tosupport a second disc 8 which is capable of axialbut non-r tative movement with respect to the shaft. The disc 8 isspirally threaded-to receive the spiral threads on the end of the rod sothat axial movement of the disc 8 produces a rotation of the rod 4.Carried by two of the pins 7 are governor balls 9 which are designed tobe affected by the centrifugal force developed by the rotation of theshaft 1. The balls carry links 10 which are pivoted about the pin 7through the intermediary of hinges 11, and also fingers 12, so fashionedthat as the balls move outwardly, due to centrifugal force actingthereon, the fingers are caused to press against the disc 8 to move itaxially a with respect to the shaft 1'. Springs 13 positioned around thepins 7 and interposed between discs 5 and 8 tend to urge the disc 8 intoits position farthest-removed from the end of the shaft 1 or in otherwordsfrom disc 5. Movement of the disc 8,elfected by a variation in thespeed of rotation of cam shaft 11, because of the threaded relation ofdisc 8 and rod 4 brings about a rotation of said rod to produce avariation in the extent of the dwell of the cam, broadly designated asB, as will be more clearly hereinafter set forth. I

The cam is comprised by two parts 14-and 15, the part 14 designedto bepositioned on the cam shaft and fixed relatively thereto, by means of akeyway 16, and a set-screw 17 and the part 15, constructed so as to becapable of rotation about the shaft 1 for a purpose that will appear asthe description progresses. The fixed cam part is furnished with atongue 18 which when theltwo parts are together is received in a groove19in the movable cam part 15, andwhich in certam positions of the partsforms a portion 7 of the cam dwellQ Part isprovided with acircumferential skirtflange 20 designed to overlie cam part 14andformabearing for the part 15 as it rotates aboutpart ,14, thatportion of 14 on which the skirtbearsbeing the arc ofa circlewhosewcenter the mid point of the cam shaft, consequently :the movementof cam part 15 about part14-constitutes circular motion about thesaidshaft, For the purpose of-guiding the movable part 15 with respectto thefixed part let-slots 22 and 28 are provided in the skirt 20 forthepurpose a of accommodating pins 24* and i with which the fixedcam-part is provided: For controlling-the extent of rotation of onesteps 27 in the part ;15. WVhen the dwell of the cam is the smallest,that is, when the tongue 18 is inserted to its greatest extent in thegroove 19 the steps are removed in a circumferential manner from eachother or in other words a space exists between them. The fixed part 14carries a slot 28 designed to accommodate a pin 29 on rod 4 for apurpose which presently will appear. The

pin 29 is afiixed to the rod 4 and passes through slot 28 in fixed part14 into movable part 15 sothat when rod 4 is rotated part 15 isconstrained to move with respect to part 14, the pin 29 in this movementsliding along the slot 28, and skirt 2O riding aboutcam part 14. i

To simplify the assemblage of the cam upon the cam shaft the pin 29 isthreaded so as to be capable of being screwed into a threaded hole inthe rod 4. In order that access may be had for this operation, cam part15 is bored out at 30 and provided with an internal shoulder 31 for thereception of a head on the pin. p I

To provide for the lubrication of the movable parts the rod 4 asbefore-mentioned is furnished with an opening 6 through which oil may beintroduced in any known manner.

The pin 29 likewise bears an oil passage 32 which is in communication,through holes 33 drilled therein, with the passage in the rod. Oilintroduced to the passage in the rod 4 is impelled against and into themovabl Parts by centrifugal force with. the result that surfaces subject to friction are thoroughly lubricated. The operation of the deviceis'as follows As the speed of the cam shaft varies due to fluctuationsin the rate of rotation of the engine crank shaft the governor balls aremoved axially with respect to the shaft and transmit this motion to disc8 through the intermediaryof links 10 and fingers 12. Movement of thedisc 8 due to its threaded relation with rod 4 brings about a relativerotation of the rod with respect to the cam shaft and this movement istransmitted by means of the pin 29 to the movable cam part to withdrawor further insert the tongue 18 in the groove 19 to vary the dwell ofthe cam. Variation in the dwell of the cam effects a greater or lesserperiod of intake or exhaust of the engine valves due to the fact thatthe valves receive their actuation from the valve tappet 34 which ridesover the cam surface on roller From the foregoing description it can "bereadily seen that my invention is particularly adapted to the controlof'enginevalves'because any number of cams are susceptible of beingstationed on the same cam shaft in diverse angular relation and when sopositioned are capableof beinginfiuenced by the same actuating rodthrough a multiplicity of pins aflixed thereto.

Having described my invention, what I claim as new and wish to secure byLetters Patent is:

1. In an articulated variable cam, one part designed to be fixed andcarrying a tongue which in certain relations of the parts constitutes aportion of the cam dwell, a second part oscillatable with respect to thefirst part and provided with a groove and a circumferential skirtflange, the groove receiving there in the tongue, and the flangeoverlying the first mentioned part and forming a bearing in theoscillation of the second mentioned part.

2. In a segmental cam, a fixed part and an oscillatable part, a slotinthe fixed part, a pin fixed to the movable part and projecting throughthe slot and means whereby the pin may be oscillated to effect anoscillation of the second mentioned part to vary the dwell of the cam.

3. In an articulated variable dwell cam, a fixed part provided withguide pins, an oscillatable part furnished with guide slotsand a skirtflange, the pins adapted to engage in the slots and the flange designedto embrace the fixed part whereby the parts are guided and journalledwith respect to each other.

I. An articulated variable dwell cam comprising a fixed and acircumferentially adjustable part and means including a hollow rodassociated therewith through which the surfaces of the movable parts arelubricated and relatively adjusted.

5. A segmental cam comprising a fixed and a movable part, a tongue onthe fixed part, a

groove on the movable part, the tongue sliding in the groove and formingpart of the 4 cam dwell in certain positions of the parts.

6. In an articulated variable dwell cam, a fixed part, and a movablepart provided with a skirt flange, the latter encompassing the fixedpart and constituting a bearing for the CHARLES s. BURNETT.

'= movable part.

